Dyes contained in hair dye compositions include acid dyes, basic dyes and oxidation dyes. In order to cause effective penetration of these dyes into the hair, the pH of the compositions should be adjusted to a highly acidic or alkaline condition. The hair treated with such compositions however loses moisture and becomes rough to the touch, and moreover, it is known that split or broken hair easily generates upon daily hair care such as shampooing or styling. Hair bleach compositions which decompose, by the action of an oxidizing agent contained therein, melanin in the hair under an acidic condition, thereby bleaching the hair, also cause a similar hair damage and deterioration in the touch.
Although many hair dye compositions and bleach compositions put on the market usually contain a silicone, an animal or vegetable extract, or a conditioning polymer for the purpose of lessening damage to the hair, they have not yet exhibited sufficient effects.